Dye remover



Patented June 16, 1931 MNETED PATENT OFFICE WOLF KRI'I'CHZEVSKY AND HAROLD C. PRUTSHAIT, OF CHICAGO, ILLINOIS, ASSIGNORS TO RIT PRODUCTS CORPORATION, 015 CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE DYE REMOVER No Drawing.

Our invention relates to a composition of matter intended for use as a color remover or stripper fo dyed fabrics.

Due to the extensive practice of this art,

both commercially and in households, there is a large and growing demand for a product that will accomplish the desired result in a satisfactory manner. The class of chemicals most generally used for this purpose is that known as sulphites, hydrosulphites and sulphoxylates. A most commonly used composition consists of a mixture of zinc dust and sodium bisulphit-e which, in a water solution, evolves hydrogen and forms a chemical known as zinc hydrosulphite. A well known chemical of this class is sodium hydrosulphite of the general formula Na s-1), known commercially in this country as lykopon, bleacan, decrolin, etc. This chemical when boiled in water either alone or in the presence of an alkali or acid erolves hydrogen according to the equation:

N32S204 and and. Hz

This substance is sold in large quantities for stripping dyes and for reducing vat dyes in dyeing and tinting. The chemical is quite efficient, but is very unstable due to its capacity of absorbing oxygen and moisture from the air, resulting in liberation of hydrogen. It is therefore necessary that the product be sold in sealed containers and that it be used promptly by the purchaser.

Many attempts have been made to obviate this difficulty and to stabilize the substance. In one instance the sodium hydrosulphite is combined with formaldehyde resulting in the formation of sodium hydrosulphite formaldehyde, otherwise known as sodium sulphoxylate. This product is somewhat more stable than hydrosulphite alone but is not stable in a practical sense.

Another method of effecting stabilization is to form normal zinc salts known as zinc hydrosulphites or protoline or zinc sulphoxylate hydrosulphi'te. These represent an improvement over lycopon but it is not stable and must be isolated from air and moisture.

In View of the fact that all of the substances heretofore mentioned are Water soluble, it

Application filed April 30, 1980. Serial No. 448,783.

has been proposed that a desired result might be secured by forming the insoluble derivatives, and zinc salts, known as basic zinc sulphoxylate hydrosulphite has been developed, otherwise known as rongalite or formoponextra. The substances are considerably more stable in air; due to the fact that they are insoluble in water. However, in order to use them they must be combined in an acid solution to neutralize the zinc s: .t and liberate the free acid. The result is a compound much weaker than straight sodium hydrosulphite. However, even these derivatives are not stable for indefinite periods in open air.

In order to merchandise a package product for household use it is diflicult, if not impossible to provide hermetic sealing. For that reason, we have for some years marketed a product under Patent No. 1,524,737 consisting of a mixture of a hydrosulphite and a solid acid-reacting substance. This product is an improvement over the art, but still not entirely satisfactory. It is for this reason that we have carried on a series of experiments looking toward the development of a stripping substance that could be marketed in package form and that would be stable under all atmospheric conditions.

As the result of our experi1nents,'we have found that the main reason for the decomposition of the hydrosulphite compounds was that the substance is hygroscopic and decomposes in the presence of air and moisture. 8 Va have, therefore, determined that if the hydrosulphite particles are enveloped in a water-proof or Water-resistant film, the oxygen of the air. and moisture will be excluded and the substance will remain stable indefinitely.

In speaking of hydrosulphites, we include under that name all compounds that belong to this class. It may include the salts of hydro-sulfurous acid of the general formula som soH' It also may include the different salts of the condensation product hydro-sulfurous acid, or its salts with formaldehyde which have the following formula.

son

omon known as formaldehyde sultoxalic acid and its salts whether sodium, zinc, calcium, etc. and formaldehyde bisulfuric acid and its salts, the formula being thereof. These compounds are known as lykopon, which is hy 'lrosulphite, decrolin or protolin, zinc hydrosulphite-sulphoxylate, or pon which is sodium sulfoxalatc forlehyde or basic zinc sulioxalate formalu'e technically known as tormoponrongalite, etc.

there are many other formulae and man er technical names but for brevity the subnces are herein called hydrosulphites, as they belong generally to the hydrosulphite class, the hypothetical hydrosulfurous acid being the parent substance of the whole class.

Ne have found that when sodium hydrosulphite or one of the derivatives heretofore mentioned is intimately mixed with an oily substance, the product will remain stable even when it is exposed to the air for practically an indefinite period. An oily substance that will accomplish this result may be a hydrocarbon such as petroleum. kerosene, or parallinc, or a metallic soap that is insoluble in water, such as aluminum stearate or or c an ordinary anhydrous soap, such sodium stearate, or a sulphonated soap or a vegetable oil, or a fatty acid like oleic acid, stearic acid, sulphonated fatty acid or a naphthenic acid or a-sulphonated petroleum residue.

We have determined that when a quantity of any of the mentioned oily substances in excess of 2 72; of the total amount of hydrosulphite, depending on the character of the oily substance, is intimately mixed therewith, an oily film is formed around each particle of the hydrosulphite thus providing an encasing envelope that serves to exclude air and moisture for practically an indefinite period. A

A product such as described can be used in that form in operations where an aqueous solution is not necessary. However, where a water solution is required it will be found desirable to first supply to the water an agent that will se we to act on the oily sutstance, and release it from its intimate association with the hydrosulphite unless the oily substance itself is soluble or disperses in an excess of water. This will permit the hydrosulphite to enter into solution and to act in the expected manner.

An agent that will act as required may consistof a substance such as an alkali like caustic soda, caustic potash, soda ash, borax,

the bath which will assist the hydrosulphite (Q dry sodium phosphate, or ammonia, or derivatives that are suitable to form a soluble soap with a free fatty acid or an oil.

In the use of this agent the oily substance is freed from the hydrosulphite and permitted to enter into solution or suspension. In the use of the saponifying agent, particularly where an excess of alkali is used, there will be formed an alkaline solution that wil assist in the stripping action.

However, in order that the product may be ,nerchandised in packages for household use it is desirable that an agent be combined with the treated hydrosulphite having the capacity for reacting with or acting upon the oily substance only when the mixture is placed in an excess of water. The agent may have the capacity of saponifying the oily substance and causing it to form a soap in which case the oily substance is detached from the hydrosulphite and the hydrosulphite is per mittcd to enter into solution.

An essential of the mixture is that an agent shall be selected that will be dormant or inactive relative to the sulphite and its oily envelope so long as the compound remains in dry mixture.

To illustrate, a compound contemplated in the last named disclosure may consist of 90 grams of sodium hydrosulphite and 10 grams of oleic acid, sulpholeic acid, castor oil, corn oil, sulphonated castor oil, stearic acid etc. These are first intimately mixed so that substantially every particle of the hydrosulphite receives a coating or envelope of the oily material. Such a compound is useful without the addition of other substances when used in a non-aqueous solvent. However, it has been found to be advantageous 'to combine in solid mixture soda ash, anhydrous borax or ammonium carbonate in sufiicient proportions to saponify the oil; or in a less proportion, in which case part of the oil may be saponified, thus forming a quantity of soap that will emulsify the remainder of the oil. Or we may prefer to utilize a substantially larger quantity of the saponifying agent, that is, more than sufficient to saponify the oil, in which case. we provide an excess of alkali in reaction. f

In the compound last described, it may occur under extreme climatic conditions that there will be a limited reaction of the solid substance before the compound is added to a bath but this will result merely in the formation or": a small quantity of soap wh ch will act to emulsily the oily substance. Even though all the oily substance became saponitied, the so-iorme-d soap would envelop the hydrosulphite and prevent the deterioration of the active ingredient. Soap is water-resistant to a small amount of water, although soluble in an excess of water. This compound, either in a solid mixture or in solution will accomplish the purpose of providing an efl'ective stripper that may be sold in packages or otherwise without deterioration.

We maly prefer to also add to the solid compoun other substances such as solvents, assistants, penetrators, and fillers, so lon as any such added substance does not inter ere with the function of the oily substance.

We have not attempted to specify or mention all possible substances that may be used. or that will function to protect the hydrosulphite from deterioration, de ending on the disclosures as made to describe ciple of the invention.

We claim:

1. A composition of matter consisting of substantially dry mixture of a stripping chemical of the hydrosulfite class, a' sapon1- fiable oily substance that will encase the individual particles of the stripping chemical and tend to exclude air and moisture therefrom, and an alkaline reacting chemical that will in a water solution saponify said substance and release the said substance from its intimate contact with said stripping chemical and permit said stripping chemical to enter into waste solution.

2. A composition of matter consisting of a hydrosulphite, a saponifiable substance capable of enveloping the particles of hydrosulphite with a film that will exclude air and moisture, and a quantity of an alkaline 1-3- acting substance which in a water solution is ca able of i-iponifying a portion of the filmorming substance.

3. A composition of matter consisting of a hydrosulphite, a saponifiable substance capable of enveloping the particles of hydrosulphite with a film that will exclude air and moisture, and a quantity of an alkaline reacting substance which in a water solution is capable of saponifying) the film-forming substance and provide the ath with an excess of alkali.

4. A composition of matter consisting of a solid mixture of hydrosulphite, a saponifiable oil that will envelop the particles of the hydrosulphite and exclude air and moisture, and soda ash.

5. A composition of matter consisting of sodium hydrosulphite, sulphonated castor oil and soda ash.

In testimony whereof we have aflixed our signatures.

WOLF KRITCHEVSKY. HAROLD C. PRUTSMAN.

the prin- 

